I posted a while back about the ACME 542 vs. Rebuilt 13x13 vs. Here's the thread if you're intrested, and below that are the results from the test.
Sorry for the delay, but as life does, it got busy. I wasn't able to get an Acme 540 for the test, but I tested the other three. I've got all the data written down from our trip at home and I'll get it all put together tonight. All I can comment on now is the "feel" of the prop.
One thing that I'll add is our top speed is actually 43 mph at 4400 RPM and not 45 when verrified by the Gps. Also, if you haven't had your prop rebuilt in a while go do it now even if you don't think it needs it. I hadn't registered any hits or dings on my older one, and it was not even on the same playing field with the 542 and the rebuilt. (I'll take this to mean that I have registered a number of small dings to the prop without noticing them, either way the prop looked fine to a visual inspection, but was not once we compared it to the other two)
The Acme 542 is a huge improvement over both the other props. Keep in mind I was comparing a 2 year old 13x13, a freshly rebuilt and balanced 13x13, and the acme 542. It was much smoother, much stronger, and much quieter.
The difference in hole shot and power is attributable to the 11.5 vs. 13 pitch. I'd heard it felt like adding 40 hp and I'll vouch for that. There was a discernable differencerence just "seat of the pants" when you give the boat power. The added power was great, and it was noticeable throughout the powerband. The Acme really shined when we put the weight in, and started pulling the rider. With the Acme 542 it was an easy pull to get the rider up and going, about 1/4 throttle was all it required. With the rebuilt and ballanced 13x13 it took about the normal 1/2-2/3 throttle. The same for the unrebuilt 13x13.
I was expecting the power, but the thing that blew me away was the smoothness and the noise reduction. Right out of the hole the 542 was much better. Jump on it and the boat goes. With the Acme 542 there was no vibration throughout the powerband and speedband. It was as ultra smooth as I've ever felt the boat. Idle, cruise or WOT, the 542 felt smooth. The rebuilt 13x13 was very smooth up to about 25 mph. Once we got above that you began to feel what I would call normal prop vibrations. WOT was ok, but with a slight noticeable vibration. Had I not been comparing it to the 542 I wouldn't have noticed them. The 2 yr old unrebuilt 13x13 was a different story. (Keep in mind no hit or dings that I know of to this prop just normal use, and the only time I'm not driving this boat is when I'm behind it sking or riding). I hadn't noticed it before, but this prop was not very smooth compared to the other two. A small shutter was present when you applied a heavy amout of throttle, and at WOT, you could feel a noticeable prop vibration.
The noise from prop vibration was all but gone with the Acme 542. All we could hear was the 351
As we added weight to the boat the vibrations increased with both of the 13x13's. I still couldn't feel one with the ACME 542.
Our Top speed stayed the same unweighted, but we do pull 150 more RPM (4550 compared to 4400)
The rudder feel was about the same between the rebuilt and the Acme 542. Only difference was in the turns the boat felt a bit more solid, I can't tell if this was an actual difference or my body wanting to feel like the $300 prop I just bought was better.
The wake at slalom speeds was a little smaller, but the rooster tail was a bit longer. I had heard one reviewer comment on this before. The wake also seemed a bit softer when crossing it. Overall I'd say I like the wake equally between the props.
Driving a slalom skier was much better. Speed control was extremely easy. The same can be said for a wakeboard rider on an aggressive cut. Only mild adjustments were required to the throttle with the Acme compared to significant adjustments with the rebuilt.
I did notice a more pronouced prop walk when reversing the boat. The first time I came to the dock was a surprise. After that I got used to it.
My overall impressions of this prop are WOW. Great buy especially if you're going to be using the boat for wakeboarding at all. If you only use for the boat is slaloming or barefooting I would get the 540. (Keep in mind that I did not have the chance to test this prop, but I can imagine the vibration elimination and feel would be comparable).
I should have the numbers all organized and up either tomorrow or the next day. If you've got questions ask away.
(Message edited by Ride_Klein on May 17, 2005)
(Message edited by Ride_Klein on May 17, 2005)